''Theristicus'' is a genus of

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s in the family

Threskiornithidae The family Threskiornithidae includes 36 species of large wading birds. The family has been traditionally classified into two subfamilies, the ibises and the spoonbills; however recent genetic studies have cast doubt on this arrangement, and hav ...

. They are found in open, grassy habitats in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. All have a long, decurved dark

bill Bill(s) may refer to: Common meanings * Banknote, paper cash (especially in the United States) * Bill (law), a proposed law put before a legislature * Invoice, commercial document issued by a seller to a buyer * Bill, a bird or animal's beak Plac ...

, relatively short reddish legs that do not extend beyond the tail in flight (unlike e.g. ''

Eudocimus ''Eudocimus'' is a genus of ibises, wading birds of the family Threskiornithidae. They occur in the warmer parts of the New World with representatives from the southern United States south through Central America, the West Indies, and South Amer ...

'' and ''

Plegadis ''Plegadis'' is a bird genus in the family Threskiornithidae. The genus name derives from Ancient Greek ''plegados'', "sickle", referring to the distinctive shape of the bill. Member species are found on every continent except Antarctica as well ...

''), and at least the back is grey.

Taxonomy

The genus ''Theristicus'' was erected by the German naturalist

Johann Georg Wagler Johann Georg Wagler (28 March 1800 – 23 August 1832) was a German herpetologist and ornithologist. Wagler was assistant to Johann Baptist von Spix, and gave lectures in zoology at the Ludwig Maximilian University of Munich after it was moved ...

in 1832 with the

black-faced ibis The black-faced ibis (''Theristicus melanopis'') is a species of bird in the family Threskiornithidae. It is found in grassland and fields in southern and western South America. It has been included as a subspecies of the similar buff-necked i ...

as the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

. The name is from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''theristikos'' meaning "of reaping". The genus contains four species.

References

* Matheu, E., & J. del Hoyo (1992). Family Threskiornithidae (Ibises and Spoonbills). pp. 472–506 in: del Hoyo, J., A. Elliott, & J. Sargatal (editors). ''Handbook of the Birds of the World.'' Vol. 1. Ostrich to Ducks. Lynx Edicions, Barcelona. Bird genera * Taxonomy articles created by Polbot {{Pelecaniformes-stub